-- Command: gauge ID/K, HELP/K, NODE/K, ATTRS/K/M, LABEL/K/F
     Gauge objects are created with this command.

        * ID [I..] - an id can be assigned to a gauge for later
          reference. The id can be any combination of up to 5
          characters.

        * HELP [I..] - with this argument help text may be defined
          which will be displayed as balloon help whenever the pointer
          is over the associated gauge. Of course, this is dependant on
          whether the user set up balloon help in the MUI preference
          settings.

        * NODE [I..] - this argument is used to specify a node in the
          guide file given in the command line argument HELP for
          `MUIRexx'. If the user positions the mouse pointer over the
          gauge and presses the help button on the keyboard then the
          guide file will be displayed at the node location.

        * LABEL [I..] - if given this label will be displayed in the
          gauge. A format specifier `%ld' may be included in the string
          which will be replaced by the current gauge level.

        * ATTRS [ISG] - with this option any MUIA attribute TAGs may be
          set or retrieved (see Attribute TAGs).

     Some useful TAGs for use with the gauge command are:

          TAG_Name =                        TAG_id          Flags Type
          
          Gauge_Current =                   0x8042f0dd /* V4  isg LONG */
          Gauge_Divide =                    0x8042d8df /* V4  isg BOOL */
          Gauge_Horiz =                     0x804232dd /* V4  i.. BOOL */
          Gauge_InfoText =                  0x8042bf15 /* V7  isg STRPTR */
          Gauge_Max =                       0x8042bcdb /* V4  isg LONG */
          
          Note: Consult MUI:Developer/Autodocs/MUI_Gauge.doc and
                MUI:Developer/C/Include/libraries/mui.h

     Example use of this command:

          window TITLE '"Test"' COMMAND '"quit"' PORT DEMO
              .
              .
              .
              group
                  slider ID SLDR
                  gauge ID GAUG LABEL '"level %ld"' ATTRS Gauge_Horiz TRUE
                  object CLASS '"Scale.mui"'
                  .
                  .
                  .
                  group HORIZ
                      group
                          label DOUBLE '"Hue:"'
                          label DOUBLE '"Saturation:"'
                      endgroup
                      group
                          gauge ID HUE ATTRS Gauge_Max 16384,
                                             Gauge_Divide 262144,
                                             Gauge_Horiz TRUE
                          gauge ID SAT ATTRS Gauge_Max 16384,
                                             Gauge_Divide 262144,
                                             Gauge_Horiz TRUE
                      endgroup
                  endgroup
              endgroup
          endwindow
          
          method ID SLDR Notify Numeric_Value EveryTime,
                         @GAUG 3 Set Gauge_Current TriggerValue